It is frequently desirable to add various metal treating materials below the surface of a melt of molten metal to clean or flux the molten metal of the melt, change the physical characteristics of the metal, or change the manner in which the molten metal solidifies. Various devices have been proposed for adding this metal treating material to the melt of molten metal in the foundry industry. One type of device which has been proposed uses a venturi which is connected to a hopper that feeds particles of the metal treating material from the hopper into the venturi while a pressurized fluid propellant passes through the venturi to entrain the particles of the metal treating material into this stream of propellant fluid and injects the treating material in the melt. When the stream of fluid propellant with the particles of metal treating material entrained therein is submerged under the surface of a molten metal, the particles of the metal treating material as well as the fluid propellant will be injected into the melt of molten metal. One of the primary problems with this type of devive is all of the fluid propellant must be ejected from the end of the discharge tube into the melt of molten metal. This frequently creates undue agitation in the molten metal that results in a detriment to the molten metal such as oxidation. This is especially true in melts of non-ferrous metals such as aluminum.